U.S. patent number 6,080,898 [Application Number 09/121,465] was granted by the patent office on 2000-06-27 for hydrogenolysis of glycerol.
This patent grant is currently assigned to Shell Oil Company. Invention is credited to Eit Drent, Willem Wabe Jager.
United States Patent |
6,080,898 |
Drent , et al. |
June 27, 2000 |
Hydrogenolysis of glycerol
Abstract
A process for the catalytic hydrogenolysis of glycerol in the
presence of a homogeneous catalyst that is based on a platinum
group metal or a compound of a platinum group metal, an anion
source, and a metal-complexing compound of the formula Q.sup.1
Q.sup.2 MQ.sup.3 (I) or Q.sup.1 Q.sup.2 MQMQ.sup.3 Q.sup.4 (II)
wherein M represents phosphorus, arsenic or antimony, Q represents
a group that is covalently bonded to both M's and having at least
two carbon atoms in the bridge and Q.sup.1 to Q.sup.4 are
independently similar or dissimilar optionally substituted
hydrocarbyl groups or Q.sup.1 and Q.sup.2 and/or Q.sup.3 and
Q.sup.4 represent similar or dissimilar optionally substituted
hydrocarbylene groups.
Inventors: |
Drent; Eit (Amsterdam,
NL), Jager; Willem Wabe (Amsterdam, NL) |
Assignee: |
Shell Oil Company (Houston,
TX)
|
Family
ID: |
8229431 |
Appl.
No.: |
09/121,465 |
Filed: |
July 23, 1998 |
Foreign Application Priority Data
|
|
|
|
|
Jul 23, 1997 [EP] |
|
|
97305508 |
|
Current U.S.
Class: |
568/861; 568/449;
568/486 |
Current CPC
Class: |
C07C
45/52 (20130101); C07C 29/60 (20130101); C07C
45/52 (20130101); C07C 47/22 (20130101); C07C
29/60 (20130101); C07C 31/10 (20130101); C07C
29/60 (20130101); C07C 31/205 (20130101) |
Current International
Class: |
C07C
29/00 (20060101); C07C 29/60 (20060101); C07C
45/00 (20060101); C07C 45/52 (20060101); C07C
031/18 (); C07C 047/22 () |
Field of
Search: |
;568/449,486,492,861,862,863 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Padmanabhan; Sreeni
Claims
What is claimed is:
1. In a process for the catalytic hydrogenolysis of glycerol in the
presence of a homogeneous catalyst, the improvement wherein the
homogeneous catalyst is based on a platinum group metal or a
compound of a platinum group metal, an anion source, and a
metal-complexing compound of the formula Q.sup.1 Q.sup.2 MQ.sup.3
(I) or Q.sup.1 Q.sup.2 MQMQ.sup.3 Q.sup.4 (II) wherein M represents
phosphorus, arsenic or antimony, Q represents a group that is
covalently bonded to both M's and has at least two carbon atoms in
the bridge, and Q.sup.1 to Q.sup.4 are independently similar or
dissimilar optionally substituted hydrocarbyl groups or Q.sup.1 and
Q.sup.2 and/or Q.sup.3 and Q.sup.4 together represent similar or
dissimilar optionally substituted hydrocarbylene groups; wherein
the process is carried out at a temperature in the range of 50 to
250.degree. C. and at a pressure in the range of 5 to 100 bar.
2. The process of claim 1 wherein the platinum group metal is
platinum or palladium.
3. The process of claim 1 wherein an acid having a pKa value of
less than 3, measured in aqueous solution at 18.degree. C., is the
anion source.
4. The process of claim 1 that is carried out in the presence of a
catalyst system comprising a halide anion as the anion source.
5. The process of claim 1 wherein each M in the metal-complexing
compound is phosphorus.
6. The process of claim 1 wherein a metal-complexing compound of
formula (II) is used.
7. The process of claim 1 wherein Q.sup.1 together with Q.sup.2,
and in case of a compound of general formula (II) Q.sup.3 together
with Q.sup.4, represent an optionally substituted hydrocarbylene
group.
8. The process of claim 1 that is carried out in the presence of
sulpholane, water or a mixture thereof.
Description
BACKGROUND OF THE INVENTION
The invention relates to a process for the catalytic hydrogenolysis
of glycerol. In particular, the invention relates to the
preparation of propylene glycols (1,2- and 1,3-propanediols) and/or
acrolein by the hydrogenolysis of glycerol.
Propylene glycols and acrolein are valuable chemicals. For
instance, 1,3-propanediol (PDO) is an attractive monomer in the
preparation of polyesters and polyurethanes. It may also be used to
prepare cyclic ethers that find use as solvent. Likewise, acrolein
and its dimer provide a valuable starting point for the synthesis
of chemicals used in textile finishing, paper treating, and the
manufacture of rubber chemicals, pharmaceuticals, plasticizers and
synthetic resins. Propylene glycols and acrolein may be prepared by
a variety of processes. For example, PDO may be prepared by the
hydroformylation of ethylene oxide, or by the hydrogenation of
3-hydroxypropionaldehyde. However, each of these processes requires
chemicals as starting point that have to be prepared separately,
often at considerable costs. Besides, the starting chemicals may
find other higher-value uses.
The chemicals industries have realised that our petrochemical
resources are not unlimited. Therefore, they focused and still
focus on natural resources as starting point for their processes.
For instance, U.S. Pat. No. 4,642,394 describes the process for the
conversion of glycerol to lower oxygenated hydrocarbons, such as
1,2- and 1,3-propanediol, by reacting glycerol with carbon monoxide
and hydrogen (in a "hydrogenolysis" reaction) in the presence of a
homogeneous catalyst containing tungsten and Group VIII metal
components. The examples of this patent document, however, reveal
the need for elevated temperatures and pressure conditions (200
centigrade, 4600 psig). The process is therefore not quite as
attractive as it could be.
The art also includes examples of hydrogenolysis processes using
heterogeneous catalysts. For instance, DE-A-4,302,464 describes the
conversion of glycerol into 1,2-propanediol and other products (but
not 1,3-propanediol) using copper chrome tablets at various
elevated temperatures and pressures. U.S. Pat. No. 5,326,912
employs a catalyst containing ruthenium, palladium and copper.
However, glycerol is produced rather than converted.
It is therefore an object of the invention to provide a process for
the conversion of glycerol to lower oxygenated hydrocarbons which
avoids the need for these elevated temperature and pressure
conditions.
BRIEF SUMMARY OF THE INVENTION
According to the invention, a process is provided for the catalytic
hydrogenolysis of glycerol in the presence of a homogeneous
catalyst that is based on a platinum group metal or a compound of a
platinum group metal, an anion, and a metal-complexing compound of
the formula Q.sup.1 Q.sup.2 MQ.sup.3 (I) or Q.sup.1 Q.sup.2
MQMQ.sup.3 Q.sup.4 (II) wherein M represents phosphorus, arsenic or
antimony, Q represents a group that is covalently bonded to both
M's and having at least two atoms in the bridge and Q.sup.1 to
Q.sup.4 are independently similar or dissimilar optionally
substituted hydrocarbyl groups or Q.sup.1 and Q.sup.2 and/or
Q.sup.3 and Q.sup.4 represent similar or dissimilar optionally
subsituted hydrocarbylene groups.
Note that the standard textbook "Advanced Organic Chemistry", by
Jerry March (3rd ed., pages 392-393) in respect of hydrogenolysis
of alcohols mentions that "the hydroxyl groups of most alcohols can
seldom be cleaved". Examples that do undergo the reaction readily
are benzyl-type alcohols. In addition, 1,3-glycols are mentioned as
being especially susceptible to hydrogenolysis, whereas tertiary
alcohols can be reduced by catalytic hydrogenolysis when the
catalyst is platinum bis(triphenylphosphine)dichloride. It is
therefore surprising that glycerol, which is not a benzyl-type
alcohol, may be converted into propylene glycols and/or acrolein.
Moreover, it is surprising that the conversion of glycerol may be
controlled to stop at the stage where the propylene glycols and/or
the acrolein are produced.
DETAILED DESCRIPTION OF THE INVENTION
In the present specification the metals of the platinum group are
defined as the metals with the atomic numbers 28, 46 and 78, i.e.
nickel, palladium and platinum. Of these, palladium and platinum
are preferred.
Examples of suitable metal sources are metal nitrates, suphates,
sulphonates, metal salts carboxylic acids with up to 12 carbon
atoms, or inorganic metal complexes, e.g. with carbon monoxide or
acetylacetonate. Palladium(II) acetate and platinum(II)
acetylacetonate are examples of preferred metal sources.
The anion on which the catalyst is based may be obtained from
sources such as acids and salts. The anion may also stem from
platinum group metal salts, in which case both catalyst components
are provided by the same source.
Preferred anion sources in the catalyst systems of the present
invention are strong acids, i.e., acids having a pKa value of less
than 3, preferably less than 2, measured in aqueous solution at
18.degree. C. The anions derived from these acids are
non-coordinating or weakly coordinating with the metals of the
platinum group.
Typical examples of suitable anions are anions of phosphoric acid,
sulphuric acid, hydrogen halides, sulphonic acids and halogenated
carboxylic acids such as trifluoroacetic acid. Sulphonic acids are
in particular preferred, for example methanesulphonic acid,
trifluoromethanesulphonic acid, tert-butanesulphonic acid,
p-toluenesulphonic acid and 2,4,6-trimethylbenzenesulphonic acid.
Halide anions have been found particularly useful (in combination
with other anions) when water is applied as reaction solvent.
Also, complex anions are suitable, such as the anions generated by
a combination of a Lewis acid such as BF.sub.3, AlCl.sub.3,
SnF.sub.2, Sn(CF.sub.3 SO.sub.3).sub.2, SnCl.sub.2 or GeCl.sub.2,
with a protic acid, such as a sulphonic acid, e.g. CF.sub.3
SO.sub.3 H or CH.sub.3 SO.sub.3 H or a hydrogen halide such as HF
of HCl, or a combination of a Lewis acid with an alcohol. Examples
of such complex anions are BF.sub.4.sup.-, SnCl.sub.3.sup.-,
[SnCl.sub.2.CF.sub.3 SO.sub.3 ].sup.- and PF.sub.6.sup.-.
Finally, also mixtures of anions may be used; in particular the
mixture of halide anions in combination with another anion source
mentioned above.
In the metal-complexing compounds of formula (I) or (II), (each) M
is a phosphorus atom, in which case the compounds are
monophosphines or bisphosphines.
Preferably, a metal-complexing compound of the general formula (II)
is used. The bridging group in such a compound, represented by Q,
typically is composed of carbon atoms. Preferably the bridging
group contains two or three carbon atoms in the bridge.
The hydrocarbyl groups Q.sup.1 to Q.sup.4 may independently
represent various non-cyclic or cyclic groups of up to 20 carbon
atoms, preferably up to 15 carbon atoms, more preferably up to 10
carbon atoms, optionally substituted with substituents such as
alkoxy groups with 1 to 4 carbon atoms, halogen atoms or (C.sub.1
to C.sub.4 alkyl)amino groups. Examples are alkyl groups such as
ethyl, isopropyl, sec-butyl and tert-butyl groups, cycloalkyl
groups such as cyclopentyl and cyclohexyl groups, and aryl groups
such as phenyl, tolyl and naphthyl groups.
In view of the higher activity of the resulting catalyst system,
Q.sup.1 together with Q.sup.2, and in case of a compound of general
formula (II) Q.sup.3 together with Q.sup.4, preferably represent an
optionally substituted hydrocarbylene group. The hydrocarbylene
group in general comprises at least 5 ring atoms and preferably
contains from 6 to 9 ring atoms. More preferably the cyclic group
contains 8 ring atoms. Substituents, if any, are alkyl groups
having from 1 to 4 carbon atoms. As a rule, all ring atoms are
carbon atoms, but bivalent cyclic groups containing one or two
heteroatoms in the ring, such as oxygen- or nitrogen atoms, are not
precluded. Examples of suitable bivalent cyclic groups are
1,4-cyclohexylene, 1,4-cycloheptylene, 1,3-cycloheptylene,
1,2-cyclooctylene, 1,3-cyclooctylene, 1,4-cyclooctylene,
1,5-cyclooctylene, 2-methyl-1,5-cyclooctylene,
2,6-dimethyl-1,4-cyclooctylene and 2,6-dimethyl-1,5-cyclooctylene
groups.
The preferred metal-complexing compounds of formula (II) are
1,2-bis(1,4-cyclooctylenephosphino)-ethane,
1,2-bis(1,5-cyclooctylenephosphino)ethane and mixtures thereof. For
the preparation of these compounds, reference is made to known
techniques, for example the method disclosed in GB-A-1,127,965.
The quantity in which the catalyst system is used, is not critical
and may vary within wide limits. Usual amounts range from 10.sup.-8
to 10.sup.-1, preferably from 10.sup.-7 to 10.sup.-2 mole atom of
platinum group metal per mole of ethylenically unsaturated
compound. The amounts of the participants in the catalyst system
are conveniently selected such that per mole atom of platinum group
metal from 0.5 to 10, preferably from 1 to 6 moles of
metal-complexing compound ligand are used, and from 0.5 to 15,
preferably from 1 to 8 moles of anion source or a complex anion
source are used.
Typically, the hydrogenolysis process is carried out under an
atmosphere that comprises or is composed of hydrogen gas. For
instance, an atmosphere of carbon monoxide and hydrogen is quite
suitable. These gases may be present in equimolar or non-equimolar
ratios, e.g. in a ratio within the range of 5:1 to 1:5.
The hydrogenolysis can be carried out at moderate reaction
conditions. Hence temperatures in the range of 50 to 250.degree. C.
are recommended, preferred temperatures being in the range of 70 to
200.degree. C. Reaction pressures in the range of 5 to 100 bar are
preferred. Lower or higher pressures may be selected, but are not
considered particularly advantageous. Moreover, higher pressures
require special equipment provisions.
In the process of the invention, the starting material and the
formed product may act as reaction diluent. Hence, the use of a
separate solvent is not necessary. However, the hydrogenolysis
reaction is conveniently
carried out in the additional presence of a solvent. As such,
saturated hydrocarbons, e.g. paraffins and isoalkanes are
recommended and furthermore alcohols, preferably having from 3 to
10 carbon atoms per molecule, such as propanol, butanol,
ethylhexanol-1, nonanol-1, or in general terms the alcohols formed
as hydrogenolysis product; ethers such as 2,5,8-trioxanonane
(diglyme), diethylether and anisole, and ketones, such as
methylbutylketone. A particularly suitable solvent or cosolvent is
water. Solvents comprising or substantially consisting of sulphones
are also quite suitable. Particular preferred sulphones are, for
example, dialkylsulphones such as dimethylsulphone and
diethylsulphone and cyclic sulphones, such as sulfolane
(tetrahydrothiophene-2,2-dioxide), sulfolene, 2-methylsulfolane and
2-methyl-4-ethylsulfolane. Mixtures of solvents may also be used,
for example a mixture of a sulphone with a protic solvent, such as
an alcohol or water.
The amount of solvent to be used in the process of the invention
may vary considerably. The experimental results provided
hereinafter are indicative for the amount of solvent preferably to
be used.
The invention will be illustrated by the non-limiting examples, as
described hereinafter. The abbreviations, used in the Tables have
the following meanings:
BCPE=1,2-bis(1,5-cyclooctylenephosphino)ethane
BBPE=1,2-bis(sec-butylphosphino)ethane
MSA=methanesulphonic acid
TFSA=trifluoromethanesulphonic acid
EXAMPLES 1 TO 5
The experiments were carried out in a 250 ml magnetically stirred
autoclave. The autoclave was charged with 30 ml glycerol, sulfolane
and water in the amounts disclosed in the Table, 0.25 mmol of
palladium(II) acetate, 0.6 mmol of complexing compound and anions
again in the amount disclosed in the table. After being flushed,
the autoclave was pressurized. Subsequently, the reactor was sealed
and the contents were heated to the pre-set temperature and
maintained at that temperature for 10 hours. After cooling, a
sample was taken from the contents of the reactor and analysed by
Gas Liquid Chromatography. Further details and the results of the
analysis can be found in the Table.
The calculated conversion rate is expressed as moles of product per
mole atom of platinum group metal and per hour, (mol/mol.h).
COMPARATIVE EXAMPLE 1
The experiment was performed substantially according to the
procedure as described above, however using 1.0 g of a
heterogeneous Pd on carbon catalyst (10% Pd on C, ex. Janssen
Chimica), 40 ml of glycerol and an atmosphere of pure hydrogen gas
(which should afford a better yield). The results are also set out
in the Table.
COMPARATIVE EXAMPLE 2
The experiment was performed substantially according to the
procedure as described above, however using 1.0 g of a
heterogeneous Ru on carbon catalyst (5% Ru on C, ex. Janssen
Chimica), 40 ml of glycerol and an atmosphere of pure hydrogen gas.
The results are also set out in the Table.
COMPARATIVE EXAMPLE 3 AND 4
The experiment was performed substantially according to the
procedure as described in example 1 of U.S. Pat. No. 4,642,394 at
the conditions mentioned above.
The autoclave was charged with 50 ml 1-methyl-2-pyrrolidinone, 20
ml glycerol, 0.58 mmol Rh(CO).sub.2 acetylacetonate, and 4 mmol
H.sub.2 WO.sub.4. The reactor is heated to about 150.degree. C. and
maintained at 60 bar of 1:2 (CO:H.sub.2) synthesis gas. After 15
hours only traces of acrolein could be detected.
When the Group 10 metal was replaced by Pd(CO).sub.2
acetylacetonate, no products could be detected at all.
CONCLUSIONS
Although not optimised, the examples according to the invention
outperform the comparative examples. Other remarks than can be made
concern the metal-complexing compound. Thus, the preferred BCPE
affords a catalyst system with a higher rate than the one based on
BBPE. The acidity to the anion source affects the rate and
selectivity to acrolein. The rate is also improved by the presence
of halide anions. Whereas the amount of water allows some control
in respect of selectivity.
TABLE I
__________________________________________________________________________
Examp Anion Temp. CO/H2 Rate Selectivity (%) No Ligand (mmol)
Solvent (ml) (.degree. C.) (bar) (mol/mol.h) A/B/C/D
__________________________________________________________________________
1 BCPE MSA (5) sulpholane (10) + 140 20/40 12.8 --/47.4/21.8/30.8
water (10) 2 BCPE MSA (2) + sulpholane (10) + 170 30/30 31.2
1.6/61.6/15.8/21.0 HCl (0.2) water (5) 3 BCPE MSA (2) + sulpholane
(10) + 170 20/40 23.5 4.2/88.8/3.5/3.5 HI (0.2) water (5) 4 BCPE
TFSA (2) + sulpholane (10) + 175 20/40 82.5 79.3/15.9/0.8/4.0 HCl
(0.2) water (5) 5 BBPE MSA (2) water (10) 170 20/40 19.4
0.8/56.8/21.2/21.2 C1 -- TFSA (2) water (5) 150 --/50 <5 traces
A & B C2 -- MSA (5) water (50) 170 --/50 <5 traces B
__________________________________________________________________________
A = acrolein; B = 1propanol; C = 1,2propanediol; D =
1,3propanediol
* * * * *